Model helicopter rotor pitch control mechanism

ABSTRACT

A model helicopter rotor pitch control mechanism is provided. The mechanism comprises a seesaw; a stabilizer bar attached to said seesaw; a mixing lever pivotally supported by said stabilizer bar, said mixing lever having a first end and a second end; an upper swash lever to which said first end is connected by way of a rod and a main rotor grip to which said second end is connected by way of said rod

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a helicopter model rotor pitchcontrol mechanism, in which the Bell-Hiller control system comprises astabilizer to improve a flying stability at the time of making acircular flight in fore/aft and left/right directions and a main rotorfor providing a helicopter with ascent/descent and thrust and moreparticularly to a helicopter model rotor pitch control mechanism forcontrolling pitch angles of the two rotors.

[0003] 2. Description of Related Art

[0004] Hereinafter, the rotor pitch control mechanism in the helicoptermodel having the conventional Bell-Hiller control system 1 will beexplained with reference to FIG. 3.

[0005] The numeral denotes an upper swash plate assembly, which shows asimilar action to a lower swash plate in the swash plate when makingup/down, left/right and forward/backward movements by means of theaileron servo and the elevator servo and the pitch servo (all notshown).

[0006] Said upper swash plate 1 is inserted into a mast 2, into which arectangular slide block 3 is inserted vertically movably such that apair of washout arms 4 are pivotally supported at opposite sides thereofsaid rectangular slide block 3. Each washout arm 4 has a first end atwhich a wash arm link 5 is pivoted to a first end thereof and a secondend at which a rod 6 is pivotally supported.

[0007] The numeral 7 denotes a center hub secured to the upper endportion of said mast 2 and, further, a yoke 8 is secured at the upperend portion of said center hub 7. Said yoke 8 is rotatably provided witha main rotor grip 9 to which main rotors are to be attached. The numeral10 denotes a see-saw pivotally supported to surround said center hub 7having opposite sides at which mixing levers 11 are pivotally supportedsubstantially centrally.

[0008] Said mixing lever 11 has a first end and a second end. Further,there is provided a rod 12 pivoted to the first end of said mixing lever11. On the other hand, there is provided an arm 13 having a first endand a second end. Said first end of the arm 13 is connected to the mainrotor grip 9 while said second end of the arm 13 is pivoted to thesecond end of said mixing lever 11.

[0009] In a plane in which said sea-saw 10 perpendicularly crosses saidmixing lever 11, a stabilizer bar 14 having opposite ends attached torespective stabilizer plates 15 and extending through a frame shapedHiller control lever 16 and the center hub 7 is secured to said Hillercontrol lever 16 in such a manner not to rotate. Therefore, thestabilizer bar 14 is allowed to rotate in response to the swing actionof the Hiller control lever 16.

[0010] Said frame shaped Hiller control lever 16 is arranged to surroundthe sea-saw 10. As mentioned above, said stabilizer bar 14 is secured tosaid frame shaped Hiller control lever 16. Said frame shaped Hillercontrol lever 16 has shaft portions parallel to said stabilize bar 14.Said rod 6 has a first end and a second end, said first end beingpivoted to said mixing bar 11 while said second end of the rod 6 ispivoted to said parallel shaft portion of the stabilizer 14.

[0011] With the thus constructed conventional rotor pitch controlmechanism, the mixing lever 11 is pivoted by way of the rod 12 inresponse to vertical movements of the upper swash plate 1 driven by thepitch servo. The pivotal movement causes the main rotor grip 9 by way ofthe rod 13 to rotate such that the pitch angle of the main rotor isvaried to cause the helicopter to ascend and descend.

[0012] It is to be noted that because the slide lock 3 is connected tothe upper swash plate 1 by way of the washout link 5, the slide lock 3also ascend and descend in response to the vertical movements of theupper swash plate 1 without influencing the change in the main rotorpitch angle.

[0013] Next, when the upper swash plate is swung left/right and fore/aftdirections by driving the aileron or elevator servo, the washout arm 4is swung in response to the rotation of the upper swash plate 1, thuscausing the Hiller control lever 16 to be swung about the stabilizer bar14 by way of the rod 6.

[0014] With the swing action of said Hiller control lever 16, the pitchangle of the stabilizer blade 15 attached to the stabilizer bar 14secured to said Hiller control lever 16 varies in response to therotation of the upper swash plate 1 such that the sea-saw 10 pivoted tothe center hub 7 is caused to be swung in accordance with the change inthe lift balance of the stabilizer blade 15 to cause the mixing lever 11pivoted to the sea-saw 10 to swing about the second end of the rod 12pivoted to the upper swash plate 1. Then, the rod 13 pivoted to thesecond end of the mixing lever 11 conveys the change in the lift balanceto the main rotor grip 9 such that the pitch angle of the main rotor 18varies with the result that the helicopter makes a circular flight inleft/right directions when the aileron servo is driven and thehelicopter makes a fore/aft flight when the elevator servo is driven.

[0015] In this way, the above-mentioned conventional model helicopterrotor pitch control mechanism is constructed in such a way that thestabilizer 14, stabilizer blade 15, the sea-saw 10, the mixing lever 11and the main rotor 18 of the pitch angle of the main rotor grip 9 ischanged by way of the Hiller control lever. Therefore, said prior artmechanism has a problem that the structure becomes too complex, requirestoo many man hours for assembly work, involves too many parts, andbecomes too costly. In addition, the area of the sea-saw becomes toolarge, making the entire structure heavy-duty.

SUMMARY OF THE INVENTION

[0016] The invention is made to solve the above mentioned problems andits object is to provide a model helicopter rotor pitch controlmechanism capable of making a substantial cost reduction whiledownsizing models as well as improving the mixing lever ration freedomwhich determines the helicopter flight characteristics due to theadvantageous sea-saw fixing position to meet extensive user needs.

[0017] The object of the model helicopter rotor pitch control mechanismof the present invention is to realize the above mentioned object andits means comprises a seesaw; a stabilizer bar attached to said seesaw;a mixing lever pivotally supported by said stabilizer bar, said mixinglever having a first end and a second end; an upper swash lever to whichsaid first end is connected by way of a rod and a main rotor grip towhich said second end is connected by way of said rod.

[0018] Further, said means comprises an upper swash plate; a washout armlink having a first end and a second end, said first end pivoted infacing relation to said upper swash plate, said upper swash plateperpendicularly crossing said washout arm link at a predeterminedposition; a washout arm having a first end and a second end, said firstend being pivoted to said second end of the washout arm link; a mast; aslide block having an intermediate portion vertically movable relativeto said mast, said washout arm being pivoted to said slide block; acenter hub; a sea-saw swingably provided in said center hub; astabilizer bar having opposite ends; a stabilizer blade attached to saidopposite ends of the stabilizer blade; a Hiller control lever having afirst end and a second end, said first end being connected to saidstabilizer bar and said second end being connected to said washout armby way of the rod; a mixing lever having a first end, an intermediateend and a second end, said first end being swingably connected to saidpredetermined position, said intermediate position being rotatablypivoted to said stabilizer bar; and a main rotor grip attached to thesecond end of said mixing lever by way of the rod swingably relative tosaid yoke.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019]FIG. 1 is an exploded perspective view of the model helicopterrotor pitch control mechanism of the present invention;

[0020]FIG. 2 is a perspective view of said control mechanism beingassembled; and

[0021]FIG. 3 is an exploded perspective view of the conventional rotorpitch control mechanism.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0022] Hereinafter, the structure of the model helicopter rotor pitchcontrol mechanism of the present invention will be explained withreference to FIG. 1 and FIG. 2. It is to be noted in this connectionthat the similar numerals used in FIG. 3 will be omitted.

[0023] First of all, the similar structure to those in FIG. 3 is thatone end of the washout arm 4 is pivoted to opposite sides of the upperswash plate 1 by way of the washout arm link 5, said washout arm 4having an intermediate portion pivoted to the slide block 3, a first endof the rod 6 being pivoted to a second end of said washout arm 4, saidthe other end of the rod 6 being pivoted to one end of L-shaped Hillercontrol lever 17.

[0024] Further, the stabilizer bar 14 has an intermediate portionpivoted to the mixing lever 11. Said mixing lever 11 has a first endconnected to the main rotor grip 9 by way of the rod 13 to attach themain rotor 18 thereto. On the other hand, said mixing lever also has asecond end pivoted to the tip end of the rod 12 having a first endpivoted to the position where the upper swash plate 1 perpendicularlycrosses said washout arm link 5.

[0025] With the thus constructed rotor pitch control mechanism of thepresent invention, the mixing lever 11 is swung by way of the rod 12when the pitch servo is driven to cause the upper swash plate 1 to bevertically moved. Said swing action further causes the main rotor grip 9to swing about the yoke 8 by way of the rod 13 such that the pitch angleof the main rotor 18 is varied to cause the helicopter ascend anddescend.

[0026] Next, the washout arm 4 is swung in response to the rotation ofthe upper swash plate 1 by way of the washout arm link 5 when theaileron or elevator servo is driven to cause the upper swash plate 1swings left/right or fore/aft directions. Then, the Hiller control lever17 is swung by way of the rod 6.

[0027] As a result, the stabilizer bar 14 rotatably pivoted to thesee-saw 10 is swung such that the pitch angle of the stabilizer blade 15varies in response to the revolution of the swash plate 1, thus creatinga change in the lift balance to cause the see-saw 10 pivoted to thecenter hub 7 to rotate such that the mixing lever 11 pivoted to saidsee-saw is caused to swing about the second end of the rod 12 pivoted tothe upper swash plate 11. Therefore, the rod 13 pivoted to the secondend of the mixing lever 11 conveys the change in the lift balance to themain rotor grip 9 to change the pitch angle of the main rotor 18.

[0028] Consequently, the helicopter make a circular flight in theleft/right directions when the aileron servo is driven while thehelicopter makes fore/aft flights when the elevator servo is driven.

[0029] As described in the foregoing, the present invention ischaracterized in that the first end of the mixing lever pivoted to thestabilizer attached to the see-saw is connected to the upper swash platewhile the second end thereof is connected to the main rotor grip by wayof the rod such that the change in the lift balance is, when generated,conveyed to the main rotor grip to change the pitch angle of the mainrotor, thus improving the flight stability of the helicopter.

[0030] Further, the mixing lever is pivoted to the stabilizer barwithout being attached to the see-saw as in the prior art, easilydownsizing the see-saw as well as simplifying the production process byvirtue of simple structure, reducing the number of parts, and cuttingcosts.

What is claimed is:
 1. A model helicopter rotor pitch control mechanismcomprising a seesaw; a stabilizer bar attached to said seesaw; a mixinglever pivoted to said stabilizer bar, said mixing lever having a firstend and a second end; an upper swash lever to which said first end isconnected by way of a rod and a main rotor grip to which said second endis connected by way of said rod.
 2. A model helicopter rotor pitchcontrol mechanism comprising an upper swash plate; a washout arm linkhaving a first end and a second end, said first end pivoted in facingrelation to said upper swash plate, said upper swash plateperpendicularly crossing said washout arm link at a predeterminedposition; a washout arm having a first end and a second end, said firstend being pivoted to said second end of the washout arm link; a mast; aslide block having an intermediate portion vertically movable relativeto said mast, said washout arm being pivoted to said slide block; acenter hub; a sea-saw swingably provided in said center hub; astabilizer bar having opposite ends; a stabilizer blade attached to saidopposite ends of the stabilizer blade; a Hiller control lever having afirst end and a second end, said first end being connected to saidstabilizer bar and said second end being connected to said washout armby way of the rod; a mixing lever having a first end, an intermediateend and a second end, said first end being swingably connected to saidpredetermined position, said intermediate position being rotatablypivoted to said stabilizer bar; and a main rotor grip attached to thesecond end of said mixing lever by way of the rod swingably relative tosaid yoke.